The goal of this project is to integrate data from local research, clinical and public health entities that are screening for and treating HIV infected persons. These data will be obtained in a de- identified manner, parsed and then organized into a HIPAA compliant database containing socio- demographic, geographic, reported risk behaviors and viral sequence information. The database will update itself in real-time as new HIV infections are identified, and viral sequence data will be used to map out the phylogenetic network of our local epidemic, focusing on drug using risk groups. We will utilize a background of nationwide HIV sequences obtained from publically available repositories to improve the signal in our phylogenetic structures and use Bayesian maximum likelihood analysis to build these networks in a robust manner. Finally, we will use this system to map the socio-demographic, geographic, risk behavior and phylogenetic data to locations of newly identified acute and early HIV infections. In real-time, these results will be used to identify micro-communities and sub-networks with HIV transmission associated with injection drugs or methamphetamine use, and we will use this information to direct community specific prevention resources (i.e. needle exchange, HIV testing, education, etc.) with the ultimate goal of preventing HIV transmission clusters from developing or expanding, particularly among substance using communities. Specific Aims